The present invention generally relates to exercise machines and more particularly to machines for exercising the various groups of muscles located in the legs including the quadriceps, "gluts", and hamstrings. Numerous machines exist and have been known in the prior art for exercising the aforementioned parts of the human body. Such machines commonly utilize some sort of a movement arm moved by the body upon exertion of the legs against a resistance, typically a weight stack. Commonly, the movement arm is connected to the weight stack by an overhead cable/chain and pulley system which increases the height of the machine and also introduces a certain amount of friction in the transmission of the drive thereby reducing efficiency. Examples of such machines are shown in U.S. Pat. Nos. 4,511,137 Jones and 5,135,457 Caruso.
Certain other types of machines of the prior art use "free" weights as opposed to a weight stack. Free weights are typically interchangeable about a member on the movement arm. An example of such a machine is shown in U.S. Pat. No. 4,509,746 Mask. Although useful, "free weight" machines have certain disadvantages in that it takes a certain amount of time and effort to change the weight each time a new repetition or exercise is to be performed. Also "free weights" are not always balanced and can subject the exerciser to jerky movements which may damage the muscles or lessen the efficiency of the exercise.